In an antenna used in in-vehicle radio communication, from the viewpoint of an operating principle of the antenna, there is concern that electromagnetic radiation negatively affects a passenger in a vehicle cabin during transmission. Therefore, frequently the antenna is placed outside the vehicle such as a roof panel. However, because there is a limitation to an antenna height of the antenna projected toward the outside of the vehicle due to regulations, there is a demand for the low-profile and compact antenna.
Conventionally, in cases where the antenna that performs reception and transmission in the desired two different frequency bands is required, two resonances is obtained by providing a choke coil between antenna elements, two outputs are obtained at two frequencies using the two independent antennas, or an output is obtained by combining the two outputs at the two frequencies.